Solid solubility of the Ti₂Cr₂O₇ compound in the TiO₂-Cr₂O₃ system was investigated at a temperature range from 1300°C to 1450°C in air.
The results obtained were as follows:
1. Solid solubility of Ti₂Cr₂O₇ was observed at the temperature range from 1300° to 1450°C in air. An homogeneous solid solution of Ti₂Cr₂O₇ existed in the range of Cr₂O₃ contents from 41 to 50 wt%, 41 to 48 wt% and 41 to 46 wt% at temperatures of 1450°C, 1400°C and 1350°C, respectively.
2. Ti₂Cr₂O₇ coexisted with Ti₄Cr₂O₁₁ above 1400°C, with Ti₅Cr₂O₁₃ from 1330°C to 1400°C and with Ti₆Cr₂O₁₅ below 1330°C. 1 fig., 1 table, 5 refs.

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Phase relations in the system ZrSiO₄-TiO₂ was investigated at temperatures between 1050° and 1600°C by a quenching method. There were 3 solid phases in this system, namely ZrSiO₄, TiO_2ss, and ZrTiO_4ss. ZrSiO₄ was decomposed to ZrO₂ and SiO₂ by the abbition of TiO₂. TiO_2ss was formed up to 4wt%, 10wt%, 20wt%, and 26wt% of ZrSiO₄ at 1050°C, 1200°C, 1400°C, and 1600°C respectively. ZrTiO₄ appeared above 1400°C. The dissociated silica existed as cristobalite below 1500°C and changed into liquid above 1550°C.

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Metastable immiscibility region in the system Li₂O-B₂O₃-GeO₂ was estimated. Due to the easiness of devitrification and hygroscopic nature of lithium-boro-germanate glasses, it was very difficult to decide experimentally their metastable immiscibility region.
Using the liquidus temperature in GeO₂ primary-phase region, free energy of mixing was calculated thermodynamically for binary systems, GeO₂-B₂O₃ and -Li₂O and pseudobinary systems, GeO₂-1/4Li₂O⋅3/4B₂O₃, -1/2Li₂O⋅1/2B₂O₃, and -3/4Li₂O⋅1/4B₂O₃. Metastable miscibility gaps were determined by the co-tangent method for these binary and pseudo-binary systems and extended to the ternary system Li₂O-B₂O₃-GeO₂. The result indicated that metastable immiscibility region existed on the GeO₂-rich side at a relatively low temperature.
The region was showed in a ternary diagram. Electron microscopic observation on a few heat treated lithium-boro-germanate glasses verified the ocurrence of liquid-liquid separation in the composition that the calculation indicated.

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Cerium monosulfide Oas been prepared by the solid state reaction of cerium oxide, carbon, and cerium sesqui oxide with hydrogen sulfide. The optimum condition to prepare pure cerium monosulfide has been studies. X-ray diffraction patterns of cerium sulfides obtained from the abovementioned reactioned reactions do not agree with those reported in literatures. The cerium monosulfide thus obtained is resistant to molten aluminium at 1700°C. 2 figs., 4 tables, 7 refs.

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Some kinds of carbon fibers are produced from lignin and PVA. One graphitized and four carbonized grade fibers of this species were selected and the latters were heat-treated up to 2000°C.
The pattern of X-ray small angle scattering for the original fibers was observed only in the center, except for the following two: the graphitized grade one and the fiber the precursor of which was dried with a higher speed. With increase of heat-treatment temperature, these patterns streched isotrotropically to wider angle. A weak and circular long periodic pattern was observed for some of the heat-treated fibers.
The Porod's law held for all fibers heat-treated at 2000°C and for some fibers heat-treated at lower temperatures.
Judging from the scattering power, there would be voids in almost all fibers.
The result of the measurement of density showed that there would be open and closed pores in all fibers.
Radius of gyration varied over the range of 8-16Å. There could be pores with a larger radius of gyration in all of the fibers.
The fibers contain more or less sodium and its compounds. An elimination of them with diluted hydrochloric acid had no effect on the profile of X-ray small angle scattering and a little on density.
A wavy surface and a cross-section with pores were observed for all fibers. The surface of the original fibers were more complicated than that of their heat-treated products.

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